Cleaning Ionizer’s Emitter Pins

Regular cleaning of an ionizer’s emitter pins is necessary to stay within the ionizer’s required limits of ANSI/ESD S20.20. If the ionizer has a filter, it should be cleaned at this time as well. One S20.20 required limit for ionizers is Offset Voltage of less than + or – 50 volts (this is often referred to as “Balance”). There is also Discharge Times (both polarities) that need to be tested. The user gets to determine how many seconds the ionizer will reduce + 1,000 volts to 100 volts (and reduce – 1,000 volts to – 100 volts). Most users specify less than 10 seconds as the Required Limit for Discharge Times. Compliance Verification testing is to be performed per ESD TR53 which can be obtained as a complimentary download from

Under normal conditions, ionizers will attract dirt and dust (especially on the emitter pins). To maintain optimum performance, the emitter pin will need to be cleaned. While an ionizer may remain in balance (producing equal numbers of positive and negative ions) and not alarm, dirty and/or damaged emitter pins will prevent the ionizer from functioning correctly and producing enough ions to reduce charges from insulators and/or isolated conductors. The emitter pins should be cleaned at least every six months. However, more frequent cleaning may be required if used in environments with more contaminants.

Ammonium Nitrate Build Up

Over time electrode pins may produce a white build up.  Ammonium Nitrate is produced through a chemical interaction between the high voltage produced by the emitter pins and naturally occurring water vapor in the air.  The result is the formation of ammonium nitrate.  The ammonium nitrate can not be removed completely without dissolving ammonium nitrate with isopropyl alcohol. If the ammonium nitrate is not removed it can cause the emitter tip to melt and hinder the performance of the ionizer. 

Emitter Pin Cleaning Instructions:

Emitter pin cleaning is very simple and should be done frequently.

  2. Blow off contaminants on the emitter assemblies and fan guards with clean dry air.
  3. Brush off emitters to assure that stray filaments of cleaning material are completely removed.
  4. With a non-linting swab or small brush dipped in isopropyl alcohol wipe each emitter needle thoroughly.
  5. A soft cloth and alcohol may be used to clean each fan guard.

Leave a Reply